Affiliation:
1. Laboratory of Biomimetic Catalysis & Hybrid Materials, Department of Chemistry University of Ioannina Panepistimioupoli Ioannina Greece
2. Laboratory of Physical Chemistry of Materials & Environment, Department of Physics University of Ioannina Panepistimioupoli Ioannina Greece
Abstract
AbstractSilk fiber, often acclaimed as the pinnacle of textile materials, finds contemporary applications in the textile industry, health, and cosmetics. Gallic acid (GA) is a well‐established natural antioxidant. In the present study, a novel hybrid material SFd@GA was conceptualized and produced via surface grafting of GA onto degummed silk‐fibers (SFd). Successful covalent‐grafting of gallic acid onto the silk fabric surface was confirmed through Fourier‐transform infrared, Raman, thermogravimetric analysis (TG‐DTA), and scanning electron microscopy (SEM). electron paramagnetic resonance spectroscopy demonstrates that gallic moieties grafted on SFd@GA retain their radical/redox activity. The antioxidant capacity of the hybrid material SFd@GA was validated by quantitative analysis of antioxidant hydrogen‐atom‐transfer (HAT) to DPPH radicals. Our data reveal a 550% increase in antioxidant‐HAT activity of SFd@GA versus natural intact silk fiber, and a 1400% increase in antioxidant‐HAT activity compared to the degummed silk fiber. The paramount discovery of the present work lies in the capacity for repeated utilization of the hybrid material SFd@GA, without any discernible compromise in its antioxidant‐HAT activity. Specifically, we show that SFd@GA can be employed for at least 15 consecutive cycles, retaining >98% of its HAT efficiency, for up to many days of storage under ambient conditions. We discuss this expositional performance via the controllable Hat‐activity process that we propose.